<!DOCTYPE html>

<meta name="color-scheme" content="dark">

<div style="color:white">
    <details style="color-scheme: dark">
        <summary>summary</summary>
    </details>
</div>

<div style="color:white">
    <details open style="color-scheme: dark">
        <summary>summary 2</summary>
        Example text
    </details>
</div>